A TENSE border dispute between Thailand and Cambodia, and perennial questions over military-run Myanmar, are overshadowing three-day talks among Asean foreign ministers starting here on Sunday.

The 10-member Association of South-east Asian Nations (Asean) is due to kick off their annual meeting in Singapore with a dinner from 7:00 pm before formal talks start on Monday.

High on the official agenda is a new charter which would create an EU-style economic block committed to democracy and human rights by 2015, and efforts to get aid to some two million survivors of Cyclone Nargis in Myanmar.

Asean Secretary-General Surin Pitsuwan has said the ministers could call for 'maximum restraint' from the two neighbours.

More than 500 Thai troops and well over 1,000 Cambodian soldiers are stationed around a small Buddhist pagoda leading to the ruins of a 11th-century Preah Vihear temple, where nearby land is claimed by both sides.

Cambodian government spokesman Khieu Kanharith said Phnom Penh had sent letters to the UN Security Council and General Assembly informing them of the situation, a move that sparked an angry response in Bangkok on Sunday.

'I will say no more - the complaint has reached the UN, the Thai foreign ministry will take care of the matter', Thai Prime Minister Samak Sundaravej said.

'The situation at no-man's land needs negotiation'. Defence officials from both countries plan to meet on the border on Monday to try to defuse the crisis.

But Thai government representatives here said they could not discuss whether the countries' ministers would hold talks in Singapore, while the Cambodian team was not available to comment.

'Nobody wants to have this disturbing the region', said Mr Carl Thayer from the Strategic and Defence Studies Centre of the Australian National University.

'I think there will be pressure on Cambodia or Thailand... to set up a meeting'.

Thailand is one of three member states along with Indonesia and the Philippines which has not ratified the Asean charter, which was agreed in November and sets obligations on member states for the first time.

It binds members to commitments on democracy, good governance, the rule of law and human rights, and envisages the creation of a massive free trade bloc of more than 500 million people.

Officials are hoping it can be ratified by all members at a summit later this year despite doubts that the region's disparate regimes - including communist states and the Myanmar junta - can achieve such ambitious goals.

The Philippines has said it will not ratify the charter unless Myanmar releases democracy leader Aung San Suu Kyi, who has been under house arrest for most of the past 18 years.

Asean officials have recommended the foreign ministers release a statement demanding Myanmar release all political prisoners, a move that would signal a shift from from the bloc's stance of 'positive engagement' with the junta.

But a senior official said the junta was urging ministers to drop all political issues from a joint communique and focus solely on providing more aid for cyclone victims.

'Myanmar wants to talk about the rehabilitation efforts, not about politics', he said.

Myanmar's generals earned widespread contempt by refusing to allow foreign relief workers into the country in the aftermath of Cyclone Nargis in May, a disaster that left 138,000 people dead or missing.

Asean won praise for eventually bridging the gap between the junta and the outside world by taking the lead on a joint aid mission with the military authorities and the United Nations.

The mission is expected to release its full report on the humanitarian situation in Myanmar's devastated southern delta region here on Monday.